Multilayer barrier materials with PVD or plasma coating for vacuum insulated structure

Abstract

A method of forming a vacuum insulated structure includes providing a multi-layer sheet of material comprising at least one layer of barrier material that is disposed between first and second outer layers. The barrier material and the first and second outer layers comprise thermoplastic polymers. The multi-layer sheet of material is thermoformed to form a non-planar first component. The first component is at least partially coated utilizing a plasma polymerization process or a physical vapor deposition process to improve the barrier properties of the first component. The method further includes securing a second component to the first component to form an interior space therebetween. Porous filler material is positioned in the interior space, and a vacuum is formed in the interior space.

The invention claimed is: 
     
       1. A method of forming a vacuum insulated appliance structure, the method comprising:
 providing a multi-layer sheet of material comprising at least one layer of inner barrier material disposed between first and second outer layers, wherein the inner barrier material and the first and second outer layers comprise thermoplastic polymers having thermoforming properties that permit deep draw ratio thermoforming; 
 heating and plastically forming the sheet of material to form a first component, at least a portion of which is non-planar; 
 followed by at least partially coating at least one of the first and second outer layers with an outer barrier material utilizing a plasma polymerization process or a physical vapor deposition process; 
 securing a second component to the first component to form an interior space therebetween; 
 positioning porous filler material in the interior space; 
 forming a vacuum in the interior space; and 
 sealing the first and second components together around the porous filler material to form a vacuum insulated appliance structure. 
 
     
     
       2. The method of  claim 1 , wherein:
 the outer barrier material comprises an inorganic material. 
 
     
     
       3. The method of  claim 2 , wherein:
 the outer barrier material comprises metal. 
 
     
     
       4. The method of  claim 1 , including:
 applying a protective cap over the outer barrier material. 
 
     
     
       5. The method of  claim 4 , wherein:
 the protective cap is about 10-150 microns thick. 
 
     
     
       6. The method of  claim 4 , wherein:
 the protective cap is formed by spray, PVD or plasma process. 
 
     
     
       7. The method of  claim 1 , wherein:
 the first component comprises a central portion and four sidewalls extending transversely from the central portion; 
 the second component comprises a central portion and four sidewalls extending transversely from the central portion. 
 
     
     
       8. The method of  claim 1 , wherein:
 the first component comprises a door liner; 
 the second component comprises a door wrapper. 
 
     
     
       9. The method of  claim 1 , wherein:
 the outer layers comprise at least one of HIPS or ABS, PP, PBT or PE. 
 
     
     
       10. The method of  claim 9 , wherein:
 the inner barrier material comprises at least one of PVDC, nylon, or liquid crystal polymer. 
 
     
     
       11. The method of  claim 10 , wherein:
 the at least one layer of inner barrier material comprises first and second inner barrier layers. 
 
     
     
       12. The method of  claim 11 , wherein:
 the first inner barrier layer comprises at least one of a fluoropolymer, COC, COP, or HDPE. 
 
     
     
       13. The method of  claim 12 , wherein:
 the second inner barrier layer comprises EVOH. 
 
     
     
       14. The method of  claim 11 , including:
 a tie layer disposed between the first and second inner barrier layers, wherein the tie layer comprises a tying polymer material that bonds to the first and second inner barrier materials. 
 
     
     
       15. The method of  claim 14 , wherein:
 the tying polymer material comprises modified polyolefin with functional groups whereby the tying polymer is capable of bonding to polymers and metals. 
 
     
     
       16. The method of  claim 7 , wherein:
 the first component comprises a liner of a refrigerator cabinet; 
 the second component comprises a sheet metal wrapper of a refrigerator cabinet. 
 
     
     
       17. The method of  claim 1 , wherein:
 heating and forming the sheet of material comprises a thermoforming process. 
 
     
     
       18. The method of  claim 1 , wherein:
 comprising first and second inner barrier materials, respectively, wherein the first inner barrier material is impervious to oxygen. 
 
     
     
       19. A method of forming a vacuum insulated appliance structure, the method comprising:
 providing a multi-layer sheet of material comprising at least one layer of inner barrier material disposed between first and second outer layers, wherein the inner barrier material and the first and second outer layers comprise thermoplastic polymers; 
 heating and forming the sheet of material to form a first component, at least a portion of which is non-planar; 
 followed by at least partially coating at least one of the first and second outer layers with a metal outer barrier material utilizing a plasma polymerization process or a physical vapor deposition process; 
 securing a second component to the first component to form an interior space therebetween; 
 positioning porous filler material in the interior space; 
 forming a vacuum in the interior space; and 
 sealing the first and second components together around the porous filler material to form a vacuum insulated appliance structure.